Question

a car travels with uniform velocity of 20m/s for 5s.then the brakes are applied further the car comes to rest after 8s. Use graph to find
a)the distance traveled in 5s.
b)the distance travelled after applying brakes.
c)total distance travelled.
d)find the acceleration during 5s and last 8s.
Please ans fast

Answer 1

Answer:-

Initial Velocity = 20 m/sec

Time = 5 seconds.

After 5 seconds

Initial velocity = 20 m/sec

Final velocity = 0m/sec

Time = 8seconds

(i) Distance covered in first 5 seconds

Since Body moved with uniform motion, this means that acceleration =0

So,From 2nd equation of motion :-

S = ut + 1/2 at^2

s = at ( a = 0)

s = 20 × 5

s = 100

(ii) Distance covered after breaks are applied :-

U= 20 m/sec

V = 0 m/sec

T = 8 second

So,

v = u + at

a = (v - u)/t

a = -20/8

a = -5/2

a= -2.5

(iii) Total Distance travelled=

100 + 80

180m.

iv) Acceleration during 1st 5 seconds = 0m/sec²

Acceleration during last 8 seconds = (-2.5)m/sec²